#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <assert.h>
void my_strncat(char* s1, const char* s2,int n)
{
	while (*s1 != '\0')
	{
		s1++;
	}
		int i = 0;
		for (i = 0; i < n; i++)
		{
			*s1 = *s2;
			s1++;
			s2++;
		}
}

int main()
{
	char arr1[12] = "hello";
	char arr2[] = "world";
	my_strncat(arr1, arr2,4);
	printf("%s", arr1);
	return 0;
}